Measure the item Amazon fulfils
Enter the product in its retail packaging, ready for fulfilment. Do not use the dimensions of an empty product, the supplier’s outer carton containing several units, or a shipping pallet. Small packaging changes can move a product to a different tier.
Order the measurements correctly
The calculator sorts the three dimensions from longest to shortest. This means a box entered as 8 × 25 × 18 cm is evaluated in the same way as 25 × 18 × 8 cm. Each dimension must fit the selected tier; a lightweight but very wide product is not automatically an envelope.
Actual weight and dimensional weight
Actual weight is the packaged item’s weight. Dimensional weight represents the space the product occupies. In the published UK rules, it is calculated in kilograms as length × width × height in centimetres divided by 5,000.
A 25 × 18 × 8 cm product has a dimensional weight of 0.72 kg. If its actual weight is 0.5 kg, the standard parcel calculation normally uses 0.72 kg. Envelopes, Low-Price FBA and selected category parcels have different weight rules.
Check the category as well as the size
Some fee categories have separate parcel schedules based on actual unit weight and increments. A general product and an item in a selected category can therefore have different fulfilment charges even when the packaging is identical. Choose the fee category assigned by Amazon.
Allow for measurement differences
If your packaging sits exactly at a size or weight limit, test slightly larger values. Amazon’s recorded measurements may differ from yours. Leave room for tape, protective packaging and manufacturing variation rather than pricing from an optimistic boundary case.
Use a product-specific override when needed
For a known ASIN or an account-specific arrangement, compare with Amazon’s Revenue Calculator. The manual fulfilment input accepts an all-in VAT-exclusive fulfilment estimate that already includes fuel, battery and peak charges. Digital services fees remain a separate line in this calculator.
Amazon July 2026 rate card. Reviewed 14 October 2026. Your account statement remains the final reference.
Put the numbers to work
Try the Amazon UK FBA, eBay UK business or TikTok Shop UK calculator. Review every fee line and compare more than one selling scenario.